There exist several possibilities for a user to use two connections for one type of terminal, for example by manual unplugging and replugging of a terminal or by using a plurality of terminals which for example are constructed identical to each other. The terminals are, for example, telephones, in particular the popular analog telephones. However the terminal may also be a processor or computer.
Narrow band connections for example with transmission rates of less than or equal to 64 kilobits/second or less than or equal to 128 kilobits/second are one type of connection. The narrow band connections are, in particular, connections of a line-switched network in which voice channels are line-switched on a lower protocol level. Broadband connections for example, i.e. connections for a transmission rate of more than 1 Mbit/s (megabit/second) constitute a further type of connection. Such broadband connections are based for example on a normal POTS connection (Plain Old Telecommunication System) or ISDN connection (Integrated Services Digital Network). Some service providers, for example internet providers, offer real-time voice transmission via the internet for example, which is also called VoIP (Voice over Internet Protocol). These voice transmission services are in turn based on broadband connections. Broadband connections are in particular connections to a data packet transmission network in which the data packets are routed on a lower protocol level using address data in the data packet.